Thread: HELP! what kind of carb do I have??

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Hey fellas! I just bought a new carb from ebay. Its supposedly a Holley 850 double pumper, completley redone. Im trying to find an id number to verify this, and buy a rebuild kit. It does not have a choke tower. the only number I can find on the main body is 6R2762 stamped on the top of the carb.

Type #4150
List #4788
6.5 power valves front and rear
#80 jets all around

wow! thanks! how did you figure that out? i did open it up. it doesnt have 80s all around...not sure about the power valves.

Originally Posted by techinspector1

Type #4150
List #4788
6.5 power valves front and rear
#80 jets all around

Just to add to Tech's specs, it's rated from the factory @ 830 cfm.
With the base plate addition, it may breath quite a bit better.
Even Holley underated thier carbs a little so if you tear it down and bring it back to specs, this should be a formadible piece to use.
Your pic shows some "shelf" time and needs to be cleaned up in all the orifices and throttle plates, etc.

so would you guys recommend some kind of rebuild kit to bring it back to specs?

Tear it down carefully first, clean up the rust and crap that's visible in the pics.....orifices in the air bleed department and make sure you rorifices in the metering blocks and base plate are clear and have no junk in them.
The blue metering block gaskets show that there are some resuable parts in this thing.
Tear it apart first and let's see what's in there.

thanks for your advice! much appreciated..i did notice a around the secondary accelerator pump. plus the secondary squirter wasnt squirting fuel...

Actually, I'm pretty sure it is a list 9380... note the big annular boosters... this is the same carb I have... the list number is normally on the choke tower but yours has been milled off (which is a good mod!) These are race carbs for stocker classes and is a very good carb capable of supporting quite a few horses. (best you could get in a 4150 until they recently came out with a 950cfm... but this is the only 4150 that came stock with the annular boosters)

850cfm 78 jets from the factory (all around or "square") 6.5 power valve 30cc primary 50cc secondary accel pumps.

To be sure, you can check the throttle bore diameter... 9380 is larger at 1-3/4" while the 4788 (830cfm) has throttle bore 1-11/16"

Here is the list sheet: http://www.holley.com/data/TechServi...%20Listing.pdf

BTW: You need to back off the primary accelerator pump adjustment... it is all bound up! Loosen the nut on top just to the point where there is no slack between the pump arm and lever. With it adjusted like that I would be surprised if the pump diaphragm isn't torn.

-Chris

Yeah definitely 9380.... 4 corner idle

thanks chris! any advice will help.. i will measure the thottle bores to make sure. i also noticed that pump arm. probably why its leakin..i think my best bet may be to get a rebuild kit,and get it cleaned up. i also noticed it has 78/80 jets in it. plus two pbs. one of which looked pretty nasty. rust etc

Holley rebuild kit p/n 3-648 will have everything you need including detailed instructions. Summit has backordered to 9/7/2009... Might try Jegs or your local auto parts store can order for you.

-Chris

wow! thanks alot! il def look into that. now to clean everything just carb cleaner,and a soft brush?

That's an add on secondary metering plate from another carb.
The base plate was a mod to convert it to a double pumper. This carb is a true vacuum secondary carb.
Where the metering blocks came from is a mystery because this has pieces from all over. To double check the throttle bores, flip it over, remove the base plate and measure the body because the base plate may be off just enough to fool you.
This can be a very workable piece, unfortunately it's been modded to the point you are going to have to tear it down to do a "ground up" to create something to be dependable.

that is a carb that I wouldn't work on and I have fixed a lot of very owner abused carbs--
My usual first step is to identify the carb, stock specs and then go from there ---this one---typical E bay stuff

Can't fault you there Jerry.
I just dug out three virgin carbs out of the core bucket. All three carbs that have that matching 5271/5275 metering block in your rear, are off of 3310 list carbs from the primary side of the carb.
This thing has hodge podge parts but can still be saved.